The present invention relates generally to the field of computer systems and, more particularly, to systems and methods for accessing SDRAM devices in such computer systems.
Accessing SDRAM devices require a very specific sequence of commands to be performed on the bus. The order of the commands presented on the bus is not fixed and varies according to the mode the SDRAM devices are configured to, the bus frequency and the type of access requested. There are also many rules about the spacing between commands with many commands having a minimum spacing between other commands and other commands having no minimum spacing. The issue is further complicated by the fact the command sequences from two different access can overlap each other. This is a feature of the SDRAM that sequences of commands need not necessarily be executed serially one after another but can overlap. This overlapping feature of SDRAM devices can greatly improve the efficiency of the accesses effectively eliminating much of the overhead associated with SDRAM memory access and improves bandwidth efficiency by exploiting the use of opening multiple banks within the SDRAM device.
Accordingly, there is a need in the art of computer systems for an improved method and system for providing access to SDRAM devices.